Small-signal Stability Analysis of Power Systems under Uncertain Renewable Generation

The increasing penetration of inverter-based resources (IBRs) is changing grid dynamics and challenging safe and reliable grid operation. Particularly, the increasing integration of IBRs may cause the small-signal stability issues resulting from the dynamic interaction between the IBR inverter controls and the power network in a power system with high penetration of IBRs. It is challenging for assessing the small-signal stability in such a power system due to the complex interaction between IBRs interconnected through the power network. The assessment complexity is further increased when considering variable IBR generation. To address the challenges, this paper proposes a method for small-signal stability analysis of a multi-IBR power system under uncertain renewable generation. First, we derive that the small-signal stability of a multi-IBR power system can be estimated based on the smallest eigenvalue of a weighted Laplacian matrix of the power network. Then, a robust optimization problem is formulated to analyze the small-signal stability of a multi-IBR power system under variable renewable generation. The efficacy of the proposed method is demonstrated on a power system with three IBRs by eigenvalue analysis and electromagnetic transient simulations.